In order to increase comfort, in recent years pneumatic seats have been developed for use in vehicles, such as long-haul trucks. Pneumatic seats comprise a pedestal that includes one or more air bag(s), a seat supported by the pedestal and a control valve for controlling the volume of the air within the air bag(s). Pneumatic seats are particularly advantageous in vehicles that are driven for extended periods of time. Because the volume and pressure of air in the air bag(s) controls the height of the driver's seat, pneumatic seats can be used to adjust seat height to suit the driver's preferences. In addition, the pressure within the air bag(s) can be adjusted to help isolate the driver from vibration and bouncing when compared to non-pneumatic seats. Isolating the driver from such vibrations and bouncing reduces the occurrence of medical injuries and lumbar pain. Simply put, the air bag(s) pedestal functions as a shock absorber that absorbs the vibration and bouncing that would normally be transferred to the driver in non-pneumatic seats.
One concern of pneumatic seats has recently been identified. In severe accidents in which a vehicle with pneumatic seats tilts severely or rolls over, a pneumatic seat may pin its occupant against the roof or other areas of the vehicle. When a vehicle is severely tilted or rolls over, the weight of the occupant and seat is removed from the air bag(s) pedestal. The pressure within the air bag(s) pedestal then causes the air bag(s) to expand, possibly pinning the occupant of the seat against the roof or other area of the vehicle. Rescue personnel are often unfamiliar with the operation of pneumatic seat control systems. Therefore, an expanding air bag(s) pedestal can hinder rescue operations.
The disadvantages of pneumatic seats in rollover type accidents has led to a need for a device that automatically releases air pressure in the pneumatic seat in the case of a rollover. The present invention is directed towards fulfilling this need.